This invention relates to an off-highway vehicle and, more particularly, to control systems for optimizing performance of off-highway vehicles.
Off-highway vehicles (OHV) are used for a plurality of purposes, such as but not limited to haul truck operations in an open pit surface mine. Such off-highway vehicles, including trolley-connected OHVs and other large traction vehicles, are commonly powered by electric traction motors coupled in driving relationship to one or more axles or motor-wheel sets of the vehicle. In the motoring or traction mode of operation, the traction motors are supplied with electric current from a controllable source of electric power, e.g., an engine-driven traction alternator/rectifier/inverter combination or, alternatively, a direct current drive source including a dc motor without an inverter. The traction motors apply torque to the vehicle wheels, which exert tangential force or tractive effort on the surface on which the vehicle is traveling (e.g., a haulage track or road), thereby propelling the vehicle in a desired direction along the right of way.
Conversely, in an electrical (i.e., dynamic) braking mode of operation, the same motors serve as axle-driven/wheel-driven electrical generators. Torque is applied to the motor shafts by their respectively associated axle-wheel sets, which then exert braking effort on the surface, thereby retarding or slowing the vehicle's progress. Because there is no suitable storage medium for the resulting generated electrical energy in a conventional off-highway vehicle or trolley-connected OHV, an electrically resistive grid (known as a dynamic braking grid or load box) is used to convert the electrical energy into heat energy, which is then vented to the atmosphere.
In contrast, hybrid OHVs and hybrid trolley-connected OHVs have the capability of storing the generated dynamic braking energy in a suitable storage element(s), such as batteries, flywheels, ultra-capacitors, and the like. This stored energy may then be used for traction and/or auxiliary systems in the OHV, thereby improving fuel efficiency. However, regardless of whether an OHV includes power storage elements and/or energy dissipative elements, such components contribute to the overall size and weight of the vehicle and thus to the costs of the vehicle. While an operator may be proficient with operating one OHV having a particular size and/or weight, the operator's proficiency may vary OHV to OHV, where the size and/or weight may vary.
Because of differences in OHVs, such as those disclosed above, as well as the skill level, experience, and/or desire of an operator, the costs of operating the OHV and achieving a specific production level may vary greatly. For example, various tests have shown that fuel burn alone can vary up to fifteen percent (15%) based on the operator alone. Considering the various physical configurations of the OHV, the fuel burn may vary further if the operator was to operate to different OHVs in a similar operating mode.
Owners and/or operators of off-highway vehicles, as well as owners of locations where such vehicles are used, such as but not limited to open pit mines, would appreciate the financial benefits realized, such as, but not limited to, a lower cost per ton to the mine, a minimization of burn rate, etc., when optimal OHV operation parameters are utilized, which may further maximize component life of individual components on the OHV.